How to Make Chocolate Swirl Marble Butter Cake

Makes 1 (PME round cake pan 6-inch) or 11b loaf pan(A)• 35g salted butter, melted• 35g whole or semi skimmed milk• 10g golden granulated sugar• 2 large egg yolks, cold• a pinch of sea salt• 1/2 tsp vanilla extract• 35g cake flour or 23g plain flour + 12g corn flour(B)• 2 large egg whites, cold• 1/4 tsp cream of tartar or 1/2 tsp lime / lemon juice / distilled vinegar• 35g golden granulated sugar,